Date: 14-15 December 2005
Location: Nueva Aldea, Concepcion, Chile
Type of event: accidental exposure to lost radiography source
Before midnight on 14 December a 90-curie iridium-192 source was being used for gammagraphy of metal components in an evaporation tower at a construction site. The source became disconnected from the equipment and fell to a 22-meter high platform. The operators continued activities without recognizing that the source was missing. About 11:20 AM on 15 December a worker found the source and directly handled it; two other workers were also in contact with it for several minutes. One of the workers took the source to the site's office. Shortly afterwards, a dosimeter carried by a Finnish worker sounded an alarm while he was close to the office, leading to identification of the lost source. On advice from the Finnish worker the source was thrown into a pipe about noon; a radiography subsequently handled the source by hand briefly while identifying it. Soon thereafter the source was successfully replaced in the shielding of a radiography container. The original worker who found the source reported warmness in the fingers of one hand 10-15 minutes after exposure, burning and swelling in one cheek and one buttock 20-30 minutes after exposure, nausea and vomiting 2 hours after exposure, and erythema on one buttock 5 hours after exposure.
The three workers most exposed were hospitalized later on 15 December, then transferred to a hospital in Santiago on 16 December. On 19 December an IAEA team visited the site, recommending the worker who found the source be transferred for medical care; he was admitted to a hospital in France on 29 December. Based on dose reconstruction this worker was estimated to have incurred a 130-150 rad whole body dose and localized doses of 94,000-160,000 rad to the skin. Whole body doses for the other two significantly exposed workers were estimated as 24 rad and 17 rad, respectively. During susequent investigation a fourth worker was identified with symptoms of radiation injury. A total of 34 workers were referred and medically tested based on the potential for exposure following accident reconstruction; only one had a dose over 10 rad. The worker who found the source was hospitalized in France until 4 May 2006; his injuries included radiation burns on the hands, legs, buttock, and face.
The second and third hospitalized workers were released 22 December, but both developed radiation burns on one hand in January 2006; one required hospitalization; both were treated and recovered. The fourth exposed individual developed a radiation burn on one foot in late December, was hospitalized in January for treatment and recovered.
Consequences: 4 injuries.
© 2006, 2011 by Wm. Robert Johnston.
Last modified 19 November 2011.
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